Folate, RBC Test
A Folate, RBC test measures folate inside red blood cells rather than in the liquid part of the blood. Because it reflects folate stored over the lifespan of those cells, clinicians use it to help evaluate longer-term folate status.
About this test
Folate is a B vitamin that the body uses for building and dividing cells, making DNA, and forming healthy red blood cells. It comes from foods such as leafy greens, beans, and fortified grains, as well as from supplements.
The test is done with a simple blood draw at a Quest patient service center. A phlebotomist collects a sample from a vein, usually in the arm, and it goes to the laboratory.
Who might consider this test?
- People often look into folate when they are exploring fatigue, certain kinds of anemia, or symptoms that a clinician wants to understand more fully.
- Because folate works closely with vitamin B12, the two are frequently considered together.
- Some choose the red blood cell version specifically because they want a marker less swayed by recent meals or a recently started supplement.
Test details
| Quest code | 466 |
|---|---|
| Methodology | Immunoassay |
| Sample type | 1 mL serum |
| Collection | Quest patient service center |
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Additional details
What this test looks at
The test measures how much folate is held inside red blood cells. Since those cells circulate for a long stretch before being replaced, the amount of folate they carry reflects status built up over an extended period rather than a single day's intake. That is the main reason a clinician might prefer this version over a serum measurement.
It helps to keep in mind what the marker describes: the folate already incorporated into existing red blood cells. It does not, on its own, explain the reason behind a given result, which is why a clinician interprets it alongside diet, other B-vitamin markers, and a person's overall health.
How it differs from serum folate
Serum folate tends to move with recent eating and can rise after a folate-rich meal or a newly started supplement. The red blood cell measurement is more insulated from those short-term swings because it reflects what was captured as the cells formed. A clinician may choose one or the other, or both, depending on whether they want a snapshot of recent intake or a steadier view of stores over time.
Order online and a physician order is included — no doctor's visit and no insurance needed. Your sample is collected at a Quest Diagnostics patient service center.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does the Folate, RBC test measure?
It measures the amount of folate held inside red blood cells. Because those cells circulate for a long time, the result reflects longer-term folate status rather than recent intake.
How is RBC folate different from serum folate?
Serum folate tends to reflect recent eating and can shift with the last few meals or a new supplement, while the red blood cell measurement reflects folate captured as the cells formed, offering a steadier view of stores.
Why are folate and vitamin B12 often considered together?
Folate and B12 work closely together in the body, so clinicians frequently look at them side by side when evaluating fatigue or certain kinds of anemia to build a fuller picture.
How is the sample collected?
Through a routine blood draw at a Quest patient service center. A phlebotomist takes a small sample from a vein in the arm and sends it to the laboratory.
Can I interpret my folate result on my own?
A result is best read by a clinician who can weigh it against symptoms, diet, and related markers. The results page is a starting point for that conversation rather than an answer on its own.
Can I get the Folate test without a doctor's visit or insurance?
Yes. The $29 cash price includes an independent physician's order, so no referral is needed, and insurance is never involved.